Conventional fuel cell systems generally lack expandability and thus, for the most part, systems are manufactured and sold in specific size (e.g., electrical power rating, heat output rating, and the like) units that are designed and manufactured for that specific size only. For example, a 1000 W system is typically designed and manufactured specifically as a 1000 W system. This creates issues at the manufacturing floor of lack of commonality of parts, stocking of non-common components, warehousing of specific size systems, and the like. Moreover, once built, these systems will operate only up to their maximum capacity without the possibility of expanding.
From a marketing point of view, conventional systems' lack of expandability is a challenge because it is difficult for such systems to adapt to consumers' rapidly changing demands for power output, form factor, and continuous improvement. Conventional systems generally do not have the ability to be upgraded in power rating or other features without the introduction of entirely new designs. This, of course, creates additional issues including issues of design certification and validation (e.g., safety certification), system testing, and the like. The undesirable results for the consumer and the manufacturer include longer times to market, increased costs and increased consumption of limited engineering resources.
Fuel cells are often used in combined heat and power (CHP) systems that provide, not only the electrical output of the fuel cell, but also garner heat produced by the fuel cell to provide a heat output. In conventional CHP systems, the heat output depends directly on the electrical output load of the fuel cell. This is a limitation, particularly in applications where a consistent heat output is desired.